Recoil loading firearm



Dec-14, 1937. SANDERS 2,101,957

RECOIL LOADING FIREARM Filed Feb. 23, 1937 2 Sheets-Sheet l J? .1. k fi 1L (ML 7 e Dec. 14, 193 7.

T. F. SANDERS RECOIL LOADING FIREARM Filed Feb. 25, 1937 2 Sheets-Sheet 2 am v Patented Dec. 14, 1937 UNITED STATES PATENT OFFICE RECOIL LOADING FIREARM Application February 23, 1937, Serial No. 127,239

In Great Britain February 26, 1936 8 Claims.

The invention relates to recoil loading firearms and is directed to means for locking and unlocking the breech bolt at the appropriate times. It is applicable equally to firearms of the type in which the movements of the locking member are controlled by an inertia member which lurches forward in relation to the gun on the recoil, and to those of the type in which the breech casing and barrel together recoil on a fixed support, the

relative movement of the recoiling parts and support controlling the action of the locking member.

According to the present invention a locking member is pivoted on the breech casing on a substantially central axis perpendicular to the longitudinal axis of the gun and makes contact by a lateral surface with an abutment provided on a part which does not at first participate in the recoil. The last-named part may be an inertia member capable of sliding longitudinally in relation to the breech casing or it may be a support on which the gun is mounted to recoil against resilient means.

"Two embodiments of the invention will be described by way of illustration in conjunction with the accompanying drawings wherein Figure l is a plan of part of the breech casing of a repeating rifle omitting parts which are not relevant to the present invention;

Figure 2 isa sectionalelevation of the same;

Figure 3 is a section taken on the line III-III of Figure 2;

Figure 4 is an inverted plan partly in section of the inertia member in the locking position;

Figure 5 is a corresponding view in the unlocking position;

Figure 6 is an end view of the locking member;

Figure '7 is a sectional elevation of the parts assembled;

. Figure 8 is a sectional elevation of part of a sub-machine gun, again omitting parts not relevant to the present invention;

Figure 9 is a corresponding plan of the same;

Figure 10 is a sectional end elevation of the same;

Figure 11 is an inverted plan showing the looking member in the locking position, and

Figure 12 is a similar view in the unlocking position.

Referring first .to Figures 1 to '7 a breech casing I is provided with longitudinal grooves 2 for guiding. a breech bolt 3 in its normal travel rearwards under theinfiuence'of the gases and fora';-q.again due to the usual re'cuperator spring (not shown). A cylindrical turret 4 on the breech casing fits a recess 5 in a locking member 6 and thus constitutes a pivot for the locking member. The outer part of the locking member is generally cylindrical but with parts cut away, leaving an incomplete skirt projecting downwards to embrace the cylindrical turret 4. The locking member 6 is provided with a forward projecting lug I abutting against a step 8 on the bolt 3. This is clearly seen in the. locking position in Fig- 10 ure 4 and in the unlocking position in Figure 5.

A diametral groove 9 is cut right across the skirt of the locking member so that when the latter is rotated to the unlocking position of Figure 5 a clear run is provided for the bolt, the lug l6 1 then also having moved aside to clear thestep 8. The pivoting of the locking member iscontrolled by an inertia member ID which will now be described.

The inertia member I0 is capable of sliding in 20 a longitudinal direction on the breech casing l and is formed as a cover with top and two sides over the breech mechanism, while its ends are open to give freedom of longitudinal movement. The depending sides of the cover 10 embrace the 25 looking member 6 and carry the actuating means for it.

A blade spring II is attached to one depending side of the cover 10 and presses against a flat I formed on one side. of the locking member 6 by 30 cutting away some of the cylindrical part. The fiat is so located that the tendency of the spring H is to keep the locking piece 6 in the locking position. This may be clearly seenby camparing Figures 4 and 5. 35

On the other side of the locking piece 6, a recess is formed to co-operate as shown with a pin l2 projecting inwards from the depending side of the cover I0 opposite to that carrying the spring ll.

When the gun is fired the recoil causes the inertia cover ID to move forward in relation to the gun I, that is to the left in Figures 4 and 5, with the result that the pin l2 makes contact 45 with the side of the recess in the side of the 7 locking piece 6, the latter being only capable of a pivoting movement in relation to the breech casing i, and thus rocks the locking piece to the unlocking position of Figure 5. Any further 50 movement is prevented by the side of the recess in. the locking member coming into contact with the hump l3 formed on the inside of the cover ID. The locking member is thus stopped in its pivoting movement at a position in which the groove 5 may be seen from theembodiment shown in Figures 8 to 12, which will now be described.

A sub-machine gun comprises a stand or support H! with trigger guard l5 and magazine I6. The breech casing l is mounted to slide on the support longitudinally by tongues and grooves H. The recoil is taken by a buffer l8 between the front end of the support and a suitable part of the breech casing. The buifer I8 restores the breech. casing together with the barrel (not shown) and other parts attached to it to the firing position after recoil. I

The bolt 3 is of square section at its rear end with a recess [9 to accommodate the end of the recuperator spring 20. A step 8 is formed on the squarevpart of the bolt to engage a lug I on the front of the locking member 6. locking member 6 is of cylindrical form with the lug l projecting in front. It is seated in a recess 2| in the upper part of thebreech casing which, with the assistance'of a screwed pin 23, serves as a bearing. The front face .of the lug l is made concentric with the locking member and the step 8 is hollowed slightly to fit it.

A blade spring II as before engages. a fiat 22 formed onthe side of the locking member and 12, so as to allow the bolt free passage to the rear. The support I4 is provided with an upward projecting part 25 carrying a pin 26 and the locking member 6 has a downward projecting pin 21 located to make contactwith the pin 26. In'the locked or firing position the pins 26 and ,21 are almost or quite in contact.

As the breech casing recoils on firing, the engagement of the pins causesthe locking member 6 to rotate until on the full compression of the bufier l8 the groove B'registers with the groove '24. The lug 1 has then" moved away sideways from the step 8 and the bolt 3 is free to execute its rearward movement for the purpose of reloading.

The breech casing is held in the recoiled position by a detent (not shown). during this rearward travel of the bolt. The 'recuperator spring- 20 then returns the bolt to the firing position, the bolt trips the detent and the blade spring I I returns the locking piece 6to the locking position so that all parts are nowready to fire the next shot.

Various modifications may be made to the weapon described within the scope of the invention. For instance where an inertia member is used provision may be made for the'latter to travel forward agreater or less distance before making engagement with the locking member, In this way any weapon may be made suitable for the ammunition to be used with it, so that the bolt lock is retained during the requisite amount of time for the best operating conditions. Actual adjustment of the distance in question could be provided on a gun, but in general it is to be re- As before the garded as a factor at the disposal of the manu facturer in preparing his detailed designs.

Moreover the inertia member, instead of being formed as a cover over the breech mechanism, might be located inside the breech casing and then a slight modification would be required to other parts described above. Another modification would be to use an anti-friction roller between the inertia member and the inclined surfaceof the locking member; the last-named surface may bea part of a ribprovided on the locking member; or'the pivot axis of the locking member may be offset a little laterally from the axis of the gun.

What'I claim is:- r 1. A bolt locking arrangement for a recoil loadingfirearm comprising a breech casing, a part not participatinginitially in the recoil, longitudinal guiding means between the said part and the breech casing, a breech bolt slidably mounted in the breech casing, a bolt locking member pivoted .on the breech casing on a substantially central axis perpendicular to the longitudinal axis of the .gun, and a lateral surface on the locking member located to contact with the part not participating initially in therecoil and so rocks the locking member. p

2. A bolt locking arrangement for a recoil loading firearm comprising a breech casing, a part not'participating initially in the recoil,.longitudinal guiding means between the said part and the breech casing, a breech bolt slidably mounted in the breech casing, a bolt locking member pivoted on the breech casing on a substantially central axis perpendicular to the longitudinal axis of the gun, a lug projecting forwards on the'locking member to make contact in the locking position with a step on the bolt, and a lateral surface on the locking member located to contact with the part not participating initially in the recoil and so rock the locking member.

3. A bolt locking arrangement for a recoil loading firearm comprising a breechcasing, a part not participating initially in'the recoil, longitudinal guiding means between the said part and the breech casing, abreech bolt slidably mounted in thelbreech casing, a bolt lockingmember pivoted on the breech casingon a substantially central axis perpendicular .to ,the longitudinal axis of the gun, agroove'being'provided on the under- "side of the locking member which registers with corresponding parts of the breech casing when inthe unlocking position to provide a free passage for' the bolt, and a lateral surface on the locking member located to contact with the part not participating initially in the recoil and so rockthe locking member. Q 4; A bolt locking arrangement for a. recoil loading firearm comprising a breech casing, an inertia .member, longitudinal guiding means betweenthe inertia member and the breech casing, a breech bolt slidably mounted in the breech casing, a bolt locking member pivoted on the breech casing on a substantially central axis perpendicular to 'the longitudinal axis of the gun and having a depression in its side, and an inward projection on the inertia member located to make contact with the depression in the sideof the locking member,

5. A bolt locking arrangement for a recoil loadlocking member pivoted on the breech casing on 1 a substantially central axis perpendicular to the longitudinal axis of the gun, a downward projection on the locking member located laterally in relation to the pivot axis and an upward projection on the support located to contact with the downward projection on the locking member on the recoil.

6. A bolt locking arrangement for a recoil loading firearm comprising a breech casing, a part not participating initially in the recoil, longitudinal guiding means between the said part and the breech casing, a breech bolt slidably mounted in the breech casing, a bolt locking member pivoted on the breech casing on a substantially central axis perpendicular to the longitudinal axis of the gun and having a flat on one side thereof and an engagement surface on the other, a blade spring on the breech casing located to engage the fiat and normally hold the locking member in the locking position, the engagement surface of the locking member being located to contact with the part not participating initially in the recoil.

7. A bolt locking arrangement for a recoil loading firearm comprising a breech casing, an inertia member, longitudinal guiding means between the inertia member and the breech casing, a breech bolt slidably mounted in the breech casing and provided with a step facing rearwards, a bolt locking member pivoted on the breech casing on a substantially central axis perpendicular to the longitudinal axis of the gun and provided with a groove on its under side to register with corresponding parts of the breech casing when in the unlocking position to provide a free passage for the bolt, a lug projecting forwards on the locking member to make contact in the locking position with the step on the bolt, the locking member also being provided with a fiat on one side and a depression on the other, a blade spring on the breech casing located to engage the flat on the side of the locking member and hold the latter normally in the locking position, and an inward projection on the inertia member located to make contact with the depression in the side of the locking member.

8. A bolt locking arrangement for a recoil loading firearm comprising a breech casing, a support for the gun, longitudinal guiding means between the breech casing and the support, a breech bolt slidably mounted in the breech casing and provided with a step facing rearwards, a bolt looking member pivoted on the breech casing on a substantially central axis perpendicular to the longitudinal axis of the gun and provided with a fiat on its side and a groove on its under side to register with corresponding parts of the breech casing when in the unlocking position to provide a free passage for the bolt, a lug projecting forwards on the locking member to make contact in the locking position with the step on the bolt, and a blade spring on the breech casing located to engage the flat on the side of the locking member and hold the latter normally in the locking position.

THOMAS FREDERICK SANDERS. 

